Loop-taker mechanism for zigzag sewing machines



Aug. 28, 1923. 1,466,149

R. M. SHARAF LOOP TAKER MECHANISM FOR ZIGZAG SEWING MACHINES Original Filed Nov. 24. 1917 2 Sheets-Sheet 1 Aug. 28, 1923. 1,466,149

R. M. SHARAF .LOOP TAKER MECHANISM FOR ZIGZAG SEWING MACHINES.

Original Filed Nov. 24. 1917 2 Sheets-Sheet 2 Patented Aug. 28, 1923. p

UNITED STATES- RALPH PA ENT oFF c M. SHARAF, or NEW YORK, N. Y., assIGNoR m 1%. M. sHarmr' MACHINE 00.,

or BOSTON, MASSACHUSETTS, A CORPORATION or aIAssaoHUsEr'rs' LOOP-TAKEE mncnaivrs u roa z'rezae sswnve MACHINES.

Application filed November 24,1917, Serial No. 203,655. Renewed December 2, 1919. Serial no. 342,015.

T 0 all whom it may concern.

Be it known that I, RALPH M. S'HARAF, a citizen of the United States, and resident of the borough and county of the Bronx, city and State of New York, have invented certain new and useful Improvements in Loop- Taker, Mechanisms for Zigzag Sewing Machines, of which the following is a specification.

My invention relates to that type of zigzag sewing machines in which a laterallymoving needle cooperates with a loop-taker or book having abodily shifting motion, in addition to turning about its own axis. Here tofore, in machines of this character, the shifting movements of the loop-taker have been in the nature of an oscillating or reciprocatory motion given to the loop-taker axis, or, to the carrier in which the looptaker is journaled. My present invention provides means for obtaining the shifting movements of the loop-taker by causing its axis to travel in a circular or rather cylindrical path, thus simplifying the mechanism and enabling it to be readily operated at high speed, inasmuch as the travel of said axis is always in the same direction.

A specific and preferred embodiment of this invention will now be described in detail with reference to the accompanying drawings, in which- Figure 1 is a plan viewof a sewing ma chine embodying my present invention (with parts omitted) Figure 2 is an elevation, partly in section on line 22 of Fig. 1, certain parts being omitted;

Figure 3 is a front elevation with parts broken away;

Figure 4 is a bottom view of certain parts shown in Fig. 2;

Figures 5 and 6 are sections onlines 5-5 and 6-'6 respectively of Fig. 2.;

The mechanism for imparting a lateral movement to the needle may be of any approved character, and in the example illustrated I have indicated two needles 10 connected rigidly with a needle bar 11 reciprocating vertically in a frame or gate 12 which oscillates about a vertical axis 13 to give the needles their lateral movement, transversely to the line of feed; or path of the fabric. This needle-jogging mechanism may be operated in any well known or approvedmanner, for instance as set forth in my application for Letters Patent of the United States,

filed April 2, 1917, Serial No. 159,058. While I have shown two needles 10, and a separate 1oop-taker cooperating with each of them, I do not wish to restrict myself to such duplicate construction.

f It will be understood that the needle-bar 11 reciprocates above thie'base plate or table 14:, the needles on their downward stroke passing through a suitable throat-plate 15. The needle movement is of the well known type, the needle receiving a lateral move 'ment between each two successive downward orstitching strokes, such lateral movements being alternately in opposite directions.

On the downward stroke,the needle comes into operative relation to'a loop-taker 16 provided with a hook 16 or 16" respectIVGIYtOPGI'fOEm the usual function in con neotion with the loop of the needle-thread.

turn therewith,'but this is not essentialr The trunnion or pin 17, 17 fits into a. corresponding vertical bore of .ashaft 19, said bore being eccentric relatively to the shaft axis, and thus the loop-t-aker 16' is connected pivotallyat its center to the shaft'19 at a distance from the axis of such shaft. The lowerend of the bore in the shaft is shown enlarged, as at 19', to provide a-shoulder forming a stop for a flange 17 at'the lower end of the center pin 17, 17 and thus preventing upward withdrawal of said pin while its sections are connected; The shaft 19 is journaled in a-vertical sleeve 20 mounted to rotate in a normally stationary bearing 21, it being understood that the outer surface of said sleeve is co-axial with its inner surface, so that rotation of the sleeve 20 will not affect the shaft 19 journaled therein. At its upperend the sleeve 20 carries a pin 20" extending into a radial groove 16 of the loop-taker, thus forming a driving connection between the sleeve and the loop V taker. Thus while the sleeve 20 rotates, the

loop-taker 16 will rotate-also, but about an axis eccentric to that of said sleeve. Rotationmay be imparted to the sleeve 20 by making it integral or rigid with a bevel be undersood as restricting myself to such specific embodiment. To secure this intermittent rotation, a mutilated gear having two toothed segments 27 of almost 180 each is made rigid or integral with the shaft 19, at the lower end thereof, the toothed segments being separated by short blocks or holding portions 27 having concave lower surfaces concentric with the shaft24 when said holding portions are in engagement withthe smooth circrunferentialportion 28 of a mutilatcdgear rigidly connected with. the adjacent bevel gear 23. This portion 28 is about 180 in extent, and is separated from the toothed portion 28, of substantially like extent, by notches 23 to insure proper mesh at the beginning of each driving period.

Considering only one of the needles and the loop-taker cooperating therewith, the operation of the mechanism described above will be as follows:

Figures 1 to 3 show the looptakers.in their extreme left-hand positions with the hooks 16 and 16" in position to cooperate with the needles which have passed through the throat-plate. i 7

-The axis of each of the looptakers is stationary in the position indicated by A. The needles go up, shift laterally to their right hand positions and then go down in'the new positions. During the interval between the rise of the needles and their succeeding downward movement the hollow shafts 19 are rotatedthroughhalf a revolution by their connections with the main driving shaft so that the axis of each of the looptakers, traveling through the circular or cylindrical are indicated at a reaches the other extreme position A which is diametricallyopposite to A with respect to the axis B about which the shaft 19 and sleeve 20 turn. Theloop-takers are thuspositioned for proper coaetion with the needles in their right hand positions. The needles then rise again above the throat-plate and are shifted laterally toward the left, preparatory to; their downward movements in their left hand positions. Prior to such movement, however, shafts 19 is again rotatedthroughhalf a revolution by its connections with the 'main duce only a half revolution of the shaft 19.

When two need'les'and two loop-takers are employed, as illustrated, the arrangement is practically a duplication of the one described above, except thatthe position of one hook '16 relatively to the plane containing the loop-taker axis and the axis of the sleeve 20,

"is substantially the reverse of the position-of the other hoolr'16", the two hooks being in positions about 180 apart, relatively to their axes, at thetirne they cooperate with the respective needles, as indicated in Figure 1.

- In certain-cases, it may be desirable to provide for an adjustment of the distance between the loop-takers, to cooperate with needles of different spacing, as when the needle holder is removable and exchangeable.

For thus adjusting the loop-takers, I have shown a mechanism of the type disclosed in my application for Letters Patent 'of the United States filed April 2, 1917, Serial No;

159,060. The normally stationary bearings 21 are slidable toward and'from each other along guideways 29 of the frameor bedplate 29, and to each of the bearings is secured rigidly a yoke 30 engaging a groove 31 of a sleeve 31 to which the adjacent gears 23 and 28. 28, are secured rigidly. Each sleeve 31 is slidable lengthwise of the shaft 24-, yet held to rotate therewitlnas by means of a key and groove. Stationary bolts 32, secured to the frame 29, extend at right angles to thepa-th of the slidable bearings 21, through slots 21" parallel to said path. The upper surface of each bearing engages the lower surface of the frame and the bearingsare normally held stationary by the upward pressure of sleeves 33, fitted to slide onsaid bolts below the bearings, and normally urged upwardby a pressure plate 34 having holes 3 1-" for the passage of thebolts. The pressure plate 34 slides on said bolts, and its central portion is engaged by the upeach of the hollow per end of a clamping or locking screw 35,

threaded into a central opening of a plate 36, likewise provided with holes 1( 36 to receive the bolts 32. The lower ends of the bolts :re screw-threaded to receive nuts '37, the function of which is to form an abutment or backing for the plate 36 when a clamping pressure is appliedby tightening the screw screw 35 is loosened. The. nuts37 are so placed as to allow a certain looseness for the movement of the plate 34 and sleeves 33 lengthwise of the bolts 32, and in the normal clamping positionthe upper surface of the plate 36 15 out of engagement with the lower surface of the pressure plate 34.

lVhefnjthe screw 35 is loosened to release the bearings 21, the latter maybe adjusted along the guideways 29. For the purpose of effecting an equal adjustment of the two bearings simultaneously. I have shown screw 38 threaded oppositely from ithecenter and screwing through lugs 21 provided on the respective bearings 21. Longitudinal movement of this screw is prevented by aligning screws 39 which form bearings supporting the screw 38 and are normally stationary, but may be adjusted lengthwise by turning them in their stationary supporting brackets 29". on the central portion of the screw 38 is secured rigidly a spiral gear 38' in mesh with a similar gear 40 on 'a shaft 40 journaled in a. stationary bearing 29 and Provided with a knurled head 40" at its outer end. By turning this head (at a time when the bearings 21 are free toslide), the shaft 40 and the screw 38 will be rotated, the ends of the screws 39 forming station ary bearings for the'ends of the screw 38. This will cause the two bearings 21 to move toward or from each other according to the direction of the rotation. but the positions of the two hearings will always remain symmetrical to astationary central plane. After adjusting the bearings to the desired distance, the screw 35 is tightened to lock' them in osition. 7

It will" be observed that the diameter 5 of the circular path described by the loop-taker axis is approximately equal to the lateral movement 00f the needle.

The particular loop-taker illustrated is" adapted to contain a bobbincase and bobbin (not shown). for a. lower thread to pro-- duce a lock-stitch in the well-known manner. However, this is not essential, as a machine having loop-takers with my novel type of motion may be operated without any thread other than the needle thread, in which case a chain-stitch is produced.

lVhile I have shown and described a preferred and satisfactory embodiment of my invention, it is obvious that changes may be made therein within the spirit and scope thereof, as defined in the appended claims.

I claim:

1. In a sewing machine, a rotary looptaker, a member mounted to turn about a stationary axis parallel to the axis about which the loop-taker rotates, said loop-taker being journaled insaid member, means-for rotating the loop-taker about its own axis, and means for turning said member to cause the loop-taker axis to travel through a closed circular path around said'stationary axis.

2.-'In a" sewing machine, a sleeve mounted to turn about a stationary axis, a shaft journaled in said sleeve coaxially and provided with an eccentric socket, a loop-taker provided with a central pin seated insaid socket, cooperating means on said sleeve and loop-taker to drive the loop-taker from said sleeve, and meansfor' turning said shaft .to alter the position of the eccentrlc socket and of the loop-taker axis.

3. In a sewingmachine, a bearing,a sleeve journale d therein, a shaftjournaled in said sleeve co-axially, a loop-taker, the central portion of said loop-taker and an eccentric portion ofsaidshaft having mating formations to keep the loop-taker axis are position eccentric to the shaft axis, cooperating means on, said sleeve and loop-taker to drive the looprtakerfrom said sleeve, and means for turning said shaft to alter the position of the eccentric socket and of the loop-taker axis, b

4. Ina sewing machine, a shaft mounted to turn about a stationary axis, a. loop-taker mounted to turn about an axis eccentric to that of said shaft, adriving connection between said shaft and said "loop-taker, and means for shifting the loop-taker axis in a closed circular path the center of which is on said stationary axis.

5. In a sewing machine, a shaft mounted to turn about a stationary axis, a loop-taker mounted ,to turn about an axis eccentric to that of saidshaft, a driving connection between said shaft and said loop-taker, and means for shifting the loop-taker axis in a closed curvilinear path. I

6'. In a sewing machine," a shaft mounted to turn about a stationary axis, a loop-taker mounted to turn about. an axis eccentric to that of said shaft, a driving connection between said shaft and said loop-taker, and means for'shifting the loop-taker axis in a closed curvilinear path surrounding said stationary axis.

In a sewing machine, a bearing, a sleeve journaled therein, a shaft journaled in said sleeve co-axially, a loop-taker, the central portion of said loop-taker and an eccentric portion of said shaft having mating formations to keep the loop-taker axis in a position eccentric to the shaft axis, mating parts on said loop-taker and sleeve, in sliding engagement with each other toward and from the center of the loop-taker, and form:

journaled therein a shaft journaled in said sleeve co-axially, a loop-taker, the central portion of said loop-taker and an eccentric portion of said shaft having mating formations to keep the loop-taker axis in a position eccentric to the. shaft axis, mating parts 7 onsaid loop-taker and sleeve, in sliding engagement with each other toward and from the center of the loop-taker, and forming a driving connection between said sleeve and loop-taker, a driving gear wheel for operatmg said sleeve, and another driving gear wheel rotating in unison with the first-named 7 gear wheel, for giving said shaft a smaller number of revolutions than said sleeve.

9. In a sewing machine, a bearing, a sleeve journaled therein, a shaft journaled in said sleeve co-axially, aloop-taker, the central portion of said loop-taker and an eccentric portion of said shaft having mating formations to keep the loop-taker axis in aposition eccentrieto the shaft axis, mating parts on said loop-taker and sleeve, in sliding engagement with each other toward and from the center of the loop-taker, and forming a driving connection between said sleeve and loop-taker, a driving gear wheel for rotating said sleeve continuously, and a mutiliated driving gear wheel, rotating in unison with the first-namedgear wheel, for

giving said shaft intermittent partial rotations, of a half-revolution each.

10. In a sewing machine, a needle having lateral movements, a rotary loop-taker arranged to cooperate with said needle, and

' means for causing the axis about. which the path the diameter of which loop-taker rotates, to travel in a circular is approximately equal to the lateral movement of the needle. 7 11. In a sewing machine,,a needle having lateral movements, a loop-taker mounted to turn and arranged to cooperate with said needle, and means for causing the axis about which the loop-taker turns, to travel in a closed path the lateral diameter of which is approximately equal to the lateral movement of the needle.

12. In a sewing machine, a needle recipros eating lengthwise and also moving transversely of the line of feed, and a loop-taker mounted to turn about an axis parallel to the needle and arranged to cooperate with said needle, and means for causing the axis about which the loop-taker turns, to travel in a closed curvilinear path the lateral diameter of which is approximately equal to the transverse movement of the needle.

13. In a sewing machine, a shaft mounted to turn about a stationary axis, a loop-taker connected to the shaft and mountedto turn about an axis eccentric to that of said shaft, and means for shifting the loop-taker axis in a continuous curvilinear path.

14:. In a sewing, maehine,.a shaft mounted to turn, about a stationary axis, a loop-taker connected to the shaft and mounted to turn about an axis eccentric to that of said shaft, and means for shifting the loop-taker axis in a closed continuous curvilinear path.

15. In a sewingma'chine, a hollow shaft mounted to turn about a stationary ax1s,a

loop-taker operatively connected to the shaft, 7

RALPH M. SHARAF.

shaft and 

